Silicon nanowires are widely used in high-speed and highly-integrated electrical components and sensors. When silicon nanowires have a diameter of 10 nm or less, a quantum confinement effect occurs and thus, quick charge transfer is possible. According to the conventional art, silicon nanowires are grown on a substrate mainly using a metal catalytic layer.
FIGS. 1 through 3 are cross sectional views illustrating a conventional method of manufacturing silicon nanowires.
Specifically, a metal catalytic layer 12, for example, a gold (Au) layer, is deposited on a substrate 10 (FIG. 1). Then the metal catalytic layer 12 is converted into catalytic metal islands 14. The catalytic metal islands 14 are self-formed at a high temperature in a nanowire growth apparatus used in a later process, for example, a thermal chemical vapor deposition apparatus. The diameter of the self-formed catalytic metal islands 14 is large, in the order of tens of nm, for example, 20 nm or larger and the areal density (number of catalytic metal islands 14 per unit area) thereof is very low, that is, 1010/cm2 (FIG. 2).
Next, a silicon source is provided to a growth apparatus for growing silicon nanowires and silicon nanowires 16 are grown on the substrate 10 using the catalytic metal islands 14 as a catalyst. The catalytic metal islands 14 support crystal growth in the silicon nanowires 16. According to the size (diameter) of the catalytic metal islands 14, the size (diameter) of the silicon nanowires 16 is determined (FIG. 3).